Define energy bin as min <= energy < max.

The energy bin is now defines as min <= energy < max, hence the maximum bin energy is not included in the bin.
Add GPha.hpp file.
Initial version of Xspec spectrum class GPha.

The GPha class handles spectra in Xspec format.
Initial version for GPha.cpp compilation.
Add an xspec module.
Add xspec module unit tests.
Exclude xspec module unit test executable.
Channel numbers start at 1.

The write() method starts now the channel numbers at 1.
Correct makefile
Initial version.
Add GArf.cpp file.
Initial version.
Add GArf.hpp class.
Add GArf unit test.
Remove debug printing in GArf unit test.
Add readmodel binary.
Save method now overwrites existing file.

Before, the save method did just append an extension as any existing file was opened on entry. Now, the save method overwrites and existing file if clobber is true.
Initial version.
Add GRmf.cpp file.
Initial version.